// Copyright (c) 2015, UChicago Argonne, LLC. All rights reserved.

// Copyright 2015. UChicago Argonne, LLC. This software was produced
// under U.S. Government contract DE-AC02-06CH11357 for Argonne National
// Laboratory (ANL), which is operated by UChicago Argonne, LLC for the
// U.S. Department of Energy. The U.S. Government has rights to use,
// reproduce, and distribute this software.  NEITHER THE GOVERNMENT NOR
// UChicago Argonne, LLC MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR
// ASSUMES ANY LIABILITY FOR THE USE OF THIS SOFTWARE.  If software is
// modified to produce derivative works, such modified software should
// be clearly marked, so as not to confuse it with the version available
// from ANL.

// Additionally, redistribution and use in source and binary forms, with
// or without modification, are permitted provided that the following
// conditions are met:

//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in
//       the documentation and/or other materials provided with the
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//     * Neither the name of UChicago Argonne, LLC, Argonne National
//       Laboratory, ANL, the U.S. Government, nor the names of its
//       contributors may be used to endorse or promote products derived
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// THIS SOFTWARE IS PROVIDED BY UChicago Argonne, LLC AND CONTRIBUTORS
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#include "profiler.h"
#include "utils.h"

void
art(const float* data, int dy, int dt, int dx, const float* center, const float* theta,
    float* recon, int ngridx, int ngridy, int num_iter)
{
    if(dy == 0 || dt == 0 || dx == 0)
        return;

    float* gridx   = (float*) malloc((ngridx + 1) * sizeof(float));
    float* gridy   = (float*) malloc((ngridy + 1) * sizeof(float));
    float* coordx  = (float*) malloc((ngridy + 1) * sizeof(float));
    float* coordy  = (float*) malloc((ngridx + 1) * sizeof(float));
    float* ax      = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* ay      = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* bx      = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* by      = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* coorx   = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* coory   = (float*) malloc((ngridx + ngridy) * sizeof(float));
    float* dist    = (float*) malloc((ngridx + ngridy) * sizeof(float));
    int*   indi    = (int*) malloc((ngridx + ngridy) * sizeof(int));
    float* simdata = (float*) malloc((dy * dt * dx) * sizeof(float));

    assert(coordx != NULL && coordy != NULL && ax != NULL && ay != NULL && by != NULL &&
           bx != NULL && coorx != NULL && coory != NULL && dist != NULL && indi != NULL &&
           simdata != NULL);

    int   s, p, d, i, n;
    int   quadrant;
    float theta_p, sin_p, cos_p;
    float mov, xi, yi;
    int   asize, bsize, csize;
    float upd;
    int   ind_data, ind_recon;

    for(i = 0; i < num_iter; i++)
    {
        // initialize simdata to zero
        memset(simdata, 0, dy * dt * dx * sizeof(float));

        preprocessing(ngridx, ngridy, dx, center[0], &mov, gridx,
                      gridy);  // Outputs: mov, gridx, gridy

        // For each projection angle
        for(p = 0; p < dt; p++)
        {
            // Calculate the sin and cos values
            // of the projection angle and find
            // at which quadrant on the cartesian grid.
            theta_p  = fmodf(theta[p], 2.0f * (float) M_PI);
            quadrant = calc_quadrant(theta_p);
            sin_p    = sinf(theta_p);
            cos_p    = cosf(theta_p);

            // For each detector pixel
            for(d = 0; d < dx; d++)
            {
                // Calculate coordinates
                xi = -ngridx - ngridy;
                yi = 0.5f * (1 - dx) + d + mov;
                calc_coords(ngridx, ngridy, xi, yi, sin_p, cos_p, gridx, gridy, coordx,
                            coordy);

                // Merge the (coordx, gridy) and (gridx, coordy)
                trim_coords(ngridx, ngridy, coordx, coordy, gridx, gridy, &asize, ax, ay,
                            &bsize, bx, by);

                // Sort the array of intersection points (ax, ay) and
                // (bx, by). The new sorted intersection points are
                // stored in (coorx, coory). Total number of points
                // are csize.
                sort_intersections(quadrant, asize, ax, ay, bsize, bx, by, &csize, coorx,
                                   coory);

                // Calculate the distances (dist) between the
                // intersection points (coorx, coory). Find the
                // indices of the pixels on the reconstruction grid.
                calc_dist(ngridx, ngridy, csize, coorx, coory, indi, dist);

                // Calculate dist*dist
                float sum_dist2 = 0.0f;
                for(n = 0; n < csize - 1; n++)
                {
                    sum_dist2 += dist[n] * dist[n];
                }

                if(sum_dist2 != 0.0f)
                {
                    // For each slice
                    for(s = 0; s < dy; s++)
                    {
                        // Calculate simdata
                        calc_simdata(s, p, d, ngridx, ngridy, dt, dx, csize, indi, dist,
                                     recon,
                                     simdata);  // Output: simdata

                        // Update
                        ind_data  = d + p * dx + s * dt * dx;
                        ind_recon = s * ngridx * ngridy;
                        upd       = (data[ind_data] - simdata[ind_data]) / sum_dist2;
                        for(n = 0; n < csize - 1; n++)
                        {
                            recon[indi[n] + ind_recon] += upd * dist[n];
                        }
                    }
                }
            }
        }
    }
    free(gridx);
    free(gridy);
    free(coordx);
    free(coordy);
    free(ax);
    free(ay);
    free(bx);
    free(by);
    free(coorx);
    free(coory);
    free(dist);
    free(indi);
    free(simdata);
}
